Compact radiator for an electronic device

ABSTRACT

A compact radiator for a coolant used in cooling an electronic device, including inlet and outlet headers, a plurality of parallel flat tubes defining coolant flow paths between the inlet and outlet headers, and serpentine fins between adjacent tubes. The tubes have a minor dimension in the range of 0.75 mm to 1.2 mm, and the fins have a height in the range of 3 mm to 7 mm. Particularly advantageously, extruded aluminum tubes have a minor dimension of 0.75 mm to 0.85 mm, the fin height of 3.0 mm to 3.25 mm, a tube major dimension on the order of 28 to 32 times the tube minor dimension, and a wall thickness of 0.15 mm to 0.25 mm.

CROSS REFERENCE TO RELATED APPLICATION(S)

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

TECHNICAL FIELD

The present invention is directed toward heat exchangers, andparticularly toward compact radiators for use in cooling electronicdevices.

BACKGROUND OF THE INVENTION AND TECHNICAL PROBLEMS POSED BY THE PRIORART

Electronic devices such as computer systems are known to generate largeamounts of heat, particularly in their processor chips. Excessive heatcan degrade the operation of the devices and, moreover, cansignificantly impact the useful life of the device, including destroyingthe electronic components if not properly cooled.

As a result, such electronic devices typically include some form ofcooling system. For example, personal computers will typically include afan to circulate air through the computer case, and the processing chipsare often mounted in a manner so that its heat may be transferred to anelement which provides increased surface area and therefore increasedheat dissipation as a result of fan blown air passing over that surfacearea.

Liquid cooling systems have also been suggested to provide such coolingfor electronic devices, where heat from the processing chips isdissipated into the liquid coolant with the coolant being circulated ina manner so as to reject the heat to air. For example, systems usingbar-plate style heat exchangers have been suggested. However, due tosagging of the cover plate of such heat exchangers, such heat exchangershave required tube minor dimensions of at least about 1.2 mm in order toprevent sagging of the cover plate and/or channel blockage due tobrazing during manufacture.

It is imperative that an adequate amount of cooling be provided withwhatever cooling system is used in order to ensure proper operation anduseful life of the device. Moreover, such requirements must be metwithin the strictly confined space of a device in which compactness haslong been an important commercial feature.

The present invention is addresses the above needs.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a compact radiator for a coolantused in cooling an electronic device is provided, including first andsecond headers, an inlet for receiving the coolant into the firstheader, an outlet for discharging the coolant from one of the first andsecond headers, a plurality of parallel flat tubes defining coolant flowpaths between the headers, and serpentine fins between adjacent tubes.The tubes have a minor dimension in the range of 0.75 mm to 1.2 mm, andthe fins have a height in the range of 3 mm to 7 mm.

In one form of this aspect of the invention, the flat tubes are extrudedaluminum.

In another form of this aspect of the invention, at least the firstheader includes a baffle, whereby the flat tubes define multiple passesfor the coolant. In a further form, the inlet, the outlet, and thebaffle are in the first header.

In still another form of this aspect of the invention, the minordimension of the tubes is in the range of 0.75 mm to 0.85 mm.

In a further form of this aspect of the invention, the fin height is inthe range of 3.0 mm to 3.25 mm.

In a further form of this aspect of the invention, the tube majordimension is on the order of 10 to 40 times the tube minor dimension. Infurther forms, the tube major dimension is on the order of 22 to 32times the tube minor dimension, or 28 to 32 times, and in a stillfurther form, the minor dimension of the tubes is in the range of 0.75mm to 0.85 mm and the fin height is in the range of 3.0 mm to 3.25 mm.

In yet another form, the tubes have a wall thickness in the range of0.15 mm to 0.25 mm.

In another aspect of the present invention, a compact radiator for acoolant used in cooling an electronic device is provided, includingfirst and second headers, an inlet for receiving the coolant into thefirst header, an outlet for discharging the coolant from one of thefirst and second headers, a plurality of parallel flat tubes definingcoolant flow paths between the headers, and serpentine fins betweenadjacent tubes. The tubes have a minor dimension in the range of 0.75 mmto 0.85 mm, and the fins having a height in the range of 3.0 mm to 3.25mm.

In one form of this aspect of the present invention, the flat tubes areextruded aluminum.

In another form of this aspect of the invention, at least the firstheader includes a baffle, whereby the flat tubes define multiple passesfor the coolant. In a further form, the inlet, the outlet, and thebaffle are in the first header.

In a further form of this aspect of the present invention, the tubemajor dimension is on the order of 10 to 40 times the tube minordimension and, in still further forms, the tube major dimension is onthe order of 22 to 32 times the tube minor dimension, or 28 to 32 times.

In yet another form of this aspect of the present invention, the tubeshave a wall thickness in the range of 0.15 mm to 0.25 mm.

In a further aspect of the present invention, a compact radiator for anelectronic device that rejects heat to a coolant is provided, includingfirst and second headers, an inlet for receiving the coolant into thefirst header, an outlet for discharging the coolant from one of thefirst and second headers, a plurality of extruded aluminum parallel flattubes each defining a plurality of coolant flow paths between theheaders, and serpentine fins between adjacent tubes. The tubes have aminor dimension in the range of 0.75 mm to 0.85 mm and a tube majordimension on the order of 22 to 32 times the tube minor dimension, andthe fins have a height in the range of 3.0 mm 3.25 mm.

In one form of this aspect of the present invention, the tube wallthickness is in the range of 0.15 mm to 0.25 mm.

In yet another aspect of the present invention, an electronic device isprovided, including at least one heat generating processor chip, acompact radiator, a liquid coolant path, and a pump adapted to circulateliquid coolant through the radiator and liquid coolant path. Theradiator includes first and second headers, an inlet for receiving thecoolant into the first header, an outlet for discharging the coolantfrom one of the first and second headers, a plurality of parallel flattubes defining flow paths between the headers, the tubes having a minordimension in the range of 0.75 mm to 1.2 mm, and serpentine fins betweenadjacent tubes, the fins having a height in the range of 3 mm to 7 mm.The liquid coolant path is defined from the radiator outlet to the atleast one processor chip and then to the radiator inlet.

In one form of this aspect of the invention, the flat tubes are extrudedaluminum.

In another form of this aspect of the invention, at least the firstheader includes a baffle, whereby the flat tubes define multiple passesfor the coolant. In a further form, the inlet, the outlet, and thebaffle are in the first header.

In another form of this aspect of the invention, the minor dimension ofthe tubes is in the range of 0.75 mm to 0.85 mm.

In still another form of this aspect of the invention, the fin height isin the range of 3.0 mm to 3.25 mm.

In a further form of this aspect of the invention, the tube majordimension is on the order of 10 to 40 times the tube minor dimension. Infurther forms, the tube major dimension is on the order of 22 to 32times, or 28 to 32 times, the tube minor dimension, and in a stillfurther form, the minor dimension of the tubes is in the range of 0.75mm to 0.85 mm and the fin height is in the range of 3.0 mm to 3.25 mm.

In yet another form, the tubes have a wall thickness in the range of0.15 mm to 0.25 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a radiator incorporating the presentinvention;

FIG. 2 is a front face view of the radiator of FIG. 1;

FIG. 3 is a top view of the radiator of FIG. 1;

FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a diagram of an electronic device incorporating a radiatorembodying the present invention; and

FIG. 7 is a partially broken away, front face view of a multi-passradiator incorporating the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A compact radiator 10 according to the present invention is illustratedin FIGS. 1-5.

The radiator 10 includes a pair of headers 14, 16, each havinginlet/outlet connectors 20, 22 for liquid coolant. Extending between theheaders 14, 16 is the radiator core 26 including a plurality of spacedparallel flat tubes 30 with serpentine fins 40 therebetween. End plates44 may be provided for strength on the top and bottom of the core 26, oradditional tubes may alternately be positioned above and below the lastrows of fins 40.

The radiator core 26 may be made of aluminum, copper, or brasscomponents. Further, the tubes 30 may be extruded, welded orfolded/brazed. Extruded aluminum tubes 30 have been found to beparticularly suitable. Moreover, though the present invention is notlimited to the following dimensions, the following radiator dimensionsmay be advantageously used in accordance with the present invention:RADIATOR DIMENSION DIMENSION RANGE Minor tube dimension 0.75 mm to 1.2mm Major tube dimension 12 to 30 mm Fin height 3 to 7 mm Tube wallthickness 0.15 mm to 0.25 mm Tube aspect ratio (major tube 10:1 to 40:1dimension to minor tube dimension) Tube pitch to tube minor dimension3:1 to 10:1

A particularly advantageous configuration tube 30 is formed by extrudingaluminum into a size having a major dimension of about 24 mm and a minordimension of 0.75 to 0.85 mm, and tube wall thicknesses of about 0.20mm. Upwards of ten separate flow paths or channels 50 (see FIG. 4) aredefined from front to back of each tube 30, having an opening height(minor dimension) of around 0.40 mm and a depth (major dimension) ofaround 2.0 mm. Serpentine fins 40 having a height in the range of 3.0 mmto 3.25 mm may be used with these tubes 30 to particular advantage.

Radiator cores 26 according to the above provide advantageous heatexchange by minimizing the air flow blockage resulting from the frontface of the tubes and may be manufactured cost-effectively, especiallyfor low volume applications.

FIG. 6 illustrates an electronic device 60 with in which a radiator 10in accordance with the present invention may be advantageouslyincorporated.

As illustrated diagrammatically, the electronic device 60 includes ahousing including at least one heat generating component, such as aprocessor chip 64, and a path or circuit 66 for coolant (e.g. liquidcoolant) which passes near the chip 64 so that the coolant absorbs heatrejected by the chip 64. The radiator 10 is a part of the path 66. Asuitable pump 70 circulates the coolant in the path 66 so that thecoolant absorbs heat as it passes by the processor chip 64, then passesto an inlet connector 22 of one header 14, then is cooled by passingthrough the tubes 30 to the other header 16, and then passes out theoutlet connector 24 back to the processor chip 64. A suitable fan 74 mayalso be provided to circulate air through the radiator core 26 tofacilitate cooling of the coolant in the tubes 30.

FIG. 7 illustrates another embodiment of a radiator 80 incorporating thepresent invention, wherein the radiator 80 is a multi-pass heatexchanger. Specifically, a two-pass radiator 80 is illustrated in FIG.7, wherein both the inlet connector 22′ and outlet connector 24′ are inthe same header 82, separated by a baffle 84. As will be appreciated bythose skilled in the art, the core 26′ of the radiator 80 may besubstantially the same as the previously described core 26, though inthis embodiment the coolant will flow from the inlet connector 22′ tothe top four (of eight as illustrated) tubes 30′, then through thesecond header 86 to the bottom four tubes 30″. Coolant exiting thebottom four tubes 30″ then is discharged through the outlet connector24′.

It should be recognized, moreover, that still further multi-passconfigurations could be used within the scope of the present invention,including more than two passes (with baffles in both headers), anddifferent numbers of tubes (including different numbers of tubes indifferent passes).

It should also be recognized that different flow directions (e.g., withvertical tubes) within the scope of the present invention.

It should be appreciated that advantageous cooling for an electronicdevice may be provided through the use of the present invention, withsuch cooling provided in a very compact space as is particularly desiredfor such devices.

Still other aspects, objects, and advantages of the present inventioncan be obtained from a study of the specification, the drawings, and theappended claims. It should be understood, however, that the presentinvention could be used in alternate forms where less than all of theobjects and advantages of the present invention and preferred embodimentas described above would be obtained.

1. A compact radiator for a coolant used in cooling an electronicdevice, comprising: first and second headers; an inlet for receiving thecoolant into said first header; an outlet for discharging the coolantfrom one of said first and second headers; a plurality of parallel flattubes defining coolant flow paths between said headers, said tubeshaving a minor dimension in the range of 0.75 mm to 1.2 mm; andserpentine fins between adjacent tubes, said fins having a height in therange of 3 mm to 7 mm.
 2. The compact radiator of claim 1, wherein atleast said first header includes a baffle, whereby said flat tubesdefine multiple passes for said coolant.
 3. The compact radiator ofclaim 2, wherein said one of said first and second headers is said firstheader, and said baffle is in said first header.
 4. The compact radiatorof claim 1, wherein said flat tubes are extruded aluminum.
 5. Thecompact radiator of claim 1, wherein said minor dimension of said tubesis in the range of 0.75 mm to 0.85 mm.
 6. The compact radiator of claim1, wherein said fin height is in the range of 3.0 mm to 3.25 mm.
 7. Thecompact radiator of claim 1, wherein the tube major dimension is on theorder of 10 to 40 times the tube minor dimension.
 8. The compactradiator of claim 7, wherein said tube major dimension is on the orderof 22 to 32 times the tube minor dimension.
 9. The compact radiator ofclaim 8, wherein: said minor dimension of said tubes is in the range of0.75 mm to 0.85 mm; and said fin height is in the range of 3.0 mm to3.25 mm.
 10. The compact radiator of claim 8, wherein said tube majordimension is on the order of 28 to 32 times the tube minor dimension.11. The compact radiator of claim 1, wherein said tubes have a wallthickness in the range of 0.15 mm to 0.25 mm.
 12. A compact radiator fora coolant used in cooling an electronic device, comprising: first andsecond headers; an inlet for receiving the coolant into said firstheader; an outlet for discharging the coolant from one of said first andsecond headers; a plurality of parallel flat tubes defining coolant flowpaths between said headers, said tubes having a minor dimension in therange of 0.75 mm to 0.85 mm; and serpentine fins between adjacent tubes,said fins having a height in the range of 3.0 mm to 3.25 mm.
 13. Thecompact radiator of claim 12, wherein at least said first headerincludes a baffle, whereby said flat tubes define multiple passes forsaid coolant.
 14. The compact radiator of claim 13, wherein said one ofsaid first and second headers is said first header, and said baffle isin said first header.
 15. The compact radiator of claim 12, wherein saidflat tubes are extruded aluminum.
 16. The compact radiator of claim 12,wherein the tube major dimension is on the order of 10 to 40 times thetube minor dimension.
 17. The compact radiator of claim 16, wherein saidtube major dimension is on the order of 22 to 32 times the tube minordimension.
 18. The compact radiator of claim 17, wherein said tube majordimension is on the order of 28 to 32 times the tube minor dimension.19. The compact radiator of claim 12, wherein said tubes have a wallthickness in the range of 0.15 mm to 0.25 mm.
 20. A compact radiator foran electronic device that rejects heat to a coolant, comprising: firstand second headers; an inlet for receiving the coolant into said firstheader; an outlet for discharging the coolant from one of said first andsecond headers; a plurality of extruded aluminum parallel flat tubeseach defining a plurality of coolant flow paths between said headers,said tubes having a minor dimension in the range of 0.75 mm to 0.85 mmand a tube major dimension on the order of 22 to 32 times the tube minordimension; and serpentine fins between adjacent tubes, said fins havinga height in the range of 3.0 mm 3.25 mm.
 21. The compact radiator ofclaim 20, wherein said tube wall thickness is in the range of 0.15 mm to0.25 mm.
 22. An electronic device, comprising: at least one heatgenerating processor chip; a compact radiator including first and secondheaders; an inlet for receiving the coolant into said first header; anoutlet for discharging the coolant from one of said first and secondheaders; a plurality of parallel flat tubes defining flow paths betweensaid headers, said tubes having a minor dimension in the range of 0.75mm to 1.2 mm; and serpentine fins between adjacent tubes, said finshaving a height in the range of 3 mm to 7 mm; a liquid coolant pathdefined from said radiator outlet to said at least one processor chipand then to said radiator inlet; and a pump adapted to circulate liquidcoolant through said radiator and liquid coolant path.
 23. Theelectronic device of claim 22, wherein at least said first headerincludes a baffle, whereby said flat tubes define multiple passes forsaid coolant.
 24. The electronic device of claim 23, wherein said one ofsaid first and second headers is said first header, and said baffle isin said first header.
 25. The electronic device of claim 22, whereinsaid flat tubes are extruded aluminum
 26. The electronic device of claim22, wherein said minor dimension of said tubes is in the range of 0.75mm to 0.85 mm.
 27. The electronic device of claim 22, wherein said finheight is in the range of 3.0 mm to 3.25 mm.
 28. The electronic deviceof claim 22, wherein the tube major dimension is on the order of 10 to40 times the tube minor dimension.
 29. The electronic device of claim28, wherein said tube major dimension is on the order of 22 to 32 timesthe tube minor dimension.
 30. The electronic device of claim 29,wherein: said minor dimension of said tubes is in the range of 0.75 mmto 0.85 mm; and said fin height is in the range of 3.0 mm to 3.25 mm.31. The electronic device of claim 29, wherein said tube major dimensionis on the order of 28 to 32 times the tube minor dimension.
 32. Theelectronic device of claim 22, wherein said tubes have a wall thicknessin the range of 0.15 mm to 0.25 mm.